Zolpidem is a non-benzodiazepine hypnotic that acts on γ-aminobutyric acid (GABA) type A (GABA_A) receptors and is widely used to treat insomnia. Our previous studies demonstrated that inflammation induced by bacterial mimetics, such as lipopolysaccharide (LPS), prolongs zolpidem-induced loss of righting reflex (LORR) in mice, suggesting that systemic inflammatory states modulate GABAergic transmission. However, it remains unclear whether viral inflammation produces similar effects. In this study, we investigated the effect of polyinosinic:polycytidylic acid (poly(I:C)), a synthetic analog of viral double-stranded RNA, on the duration of zolpidem-induced LORR in mice. Poly(I:C) administration significantly prolonged zolpidem-induced LORR. However, this prolongation was attenuated by pretreatment with bicuculline, a GABA_A receptor antagonist, and by bumetanide, an inhibitor of Na⁺-K⁺-2Cl⁻ cotransporter isoform 1 (NKCC1). In addition, we examined the mRNA expression levels of GABA_A receptor subunits, NKCC1, and K⁺-Cl⁻ cotransporter isoform 2 (KCC2) in the hippocampi of poly(I:C)-treated mice. Poly(I:C) treatment did not significantly alter the mRNA expression of major GABA_A receptor subunits but increased Slc12a2 mRNA expression, which encodes NKCC1 in the hippocampus. Importantly, poly(I:C)-induced prolongation of LORR was attenuated by bumetanide, an NKCC1 inhibitor. In conclusion, these findings suggest that viral mimetic-induced inflammation prolongs zolpidem-induced LORR, possibly through alterations in intracellular chloride homeostasis.